1. Field of Invention
The present invention relates to spectacles, and more particularly to an auxiliary frame for spectacles which comprises a retention arrangement adapted to securely retain the auxiliary frame in position on the spectacles.
2. Description of Related Arts
Auxiliary shelter frames are widely used nowadays. A conventional auxiliary shelter frame, such as clip-on sunglasses, comprises a plurality of clipping claws for detachably mounting on shortsighted or farsighted primary eyeglasses so that the wearer does not need to carry and pay for another pair of shortsighted or farsighted sunglasses. However, the metal made clipping claws may scratch the lenses of the primary eyeglasses during the mounting process.
Moreover, the auxiliary shelter frame may not be able to be securely mounted on the primary eyeglasses so that when the wearer's body is in active body movement, such as during a particular outing, the auxiliary shelter frame may fall off from the primary eyeglasses. In some unfortunate occasions, the auxiliary frame may be distorted or damaged or slightly scratched during the unintentional drop.
In order to resolve the scratching, magnetic attachments have been developed for auxiliary shelter frames so that attachment between the auxiliary shelter frame and the corresponding eyeglasses is by virtue of non-destructive magnetic force. Typically, a primary pair of magnet members is affixed on two upper side extensions of a primary spectacle frame respectively. An auxiliary shelter such as eyeglasses comprises a pair of arms for supporting on the upper side extensions for preventing the auxiliary shelter frame from moving downward relative to the primary spectacle frame, and an auxiliary pair of magnet members connected to the arms respectively for engaging with the primary magnet members of the primary spectacle frame so as to stably attach the auxiliary shelter frame to the primary spectacle frame.
The problem for this conventional art is that the wearer has to align two pairs of magnet members. If the auxiliary magnet members of the sunglasses are misaligned with the primary magnet members of the primary spectacle frame, the sunglasses will still fall down from the primary spectacle frame very easily.
Moreover, a major drawback of the eyeglasses equipped with the magnet attachment is that the primary spectacle frame needs to be altered in its original structure design so as to affix the magnet members thereon. So, inevitably, the wearer may have to buy a spectacle set including the primary eyeglasses and the auxiliary sunglasses which is much more expensive than simply buying one detachable shelter frame.
In light of the above, it is rather easy to appreciate that both types of conventional auxiliary shelter frames have different problems. The magnetic attachments were originally developed to resolve the clipping claw problem, yet they create other problems as well.